It is well known for lubricating oils to contain a number of surface active additives (including antiwear agents, dispersants, or detergents) used to protect internal combustion engines from corrosion, wear, soot deposits and acid build up. Often, such surface active additives can have harmful effects on mechanical devices (such as internal combustion engines). Harmful effects may include possible wear (in both iron and aluminium based components), bearing corrosion, increased acid accumulation (due to lack of neutralisation of combustion by-products), or increased deposit formation, or a reduction in fuel economy.
In terms of controlling deposits, the lubricant industry has a number of engine tests used to evaluate lubricant's ability to handle deposits and sludge including the Sequence VG, Sequence IIIG, Volkswagen TDI, Caterpillar 1N, and Mercedes Benz OM501LA. With recent changes to engine specifications there is an increasing demand on the lubricant to reduce deposits. For instance, the ILSAC GF-5 specification requires a 4.0 piston merit rating in the Sequence IIIG (vs. 3.5 for GF-4).
U.S. Pat. No. 3,933,662 (Lowe, published 20 Jan. 1976) discloses mono-ester polyalkoxylated compounds combined with alkaline earth metal carbonates dispersed in a hydrocarbon medium to provide lubricating compositions of superior acid neutralizing capability and rust inhibition in internal combustion engines. The internal combustion engine tested is a Sequence IIB engine. The Sequence IIB engine test evaluates valve guide rust and pitting. U.S. Pat. No. 3,933,662 does not disclose incorporation of mono-ester polyalkoxylated compounds into the process to prepare the alkaline earth metal carbonates dispersed in a hydrocarbon medium.
Numerous references teach a variety of polyalkylene glycol type compounds in lubricants. For example U.S. Pat. No. 4,305,835 (Barber et al, published 15 Dec. 1981); U.S. Pat. No. 4,402,845 (Zoleski et al., published 6 Sep. 1983); U.S. Pat. No. 4,438,005 (Zoleski et al., published 20 Mar., 1984); U.S. Pat. No. 4,479,882 (Zoleski et al., published 30 Oct., 1984); U.S. Pat. No. 4,493,776 (Rhodes, published 15 January, 1985); U.S. Pat. No. 4,973,414 (Nerger et al., published 27 Nov., 1990); U.S. Pat. No. 5,397,486 (Small, published 14 Mar., 1995); U.S. Pat. No. 2,681,315 (Tongberg, published 15 Jun., 1954); U.S. Pat. No. 2,833,717 (Whitacre, published 6 May, 1958); U.S. Pat. No. 2,921,027 (Brennan 12 Jan., 1960); U.S. Pat. No. 2,620,302 (Harle, published 2 Dec. 1952), U.S. Pat. No. 2,620,304 (Stewart et al., published 2 Dec., 1952), and U.S. Pat. No. 2,620,305 (Stewart et al., published 2 Dec., 1952). None of the references disclose incorporation of polyalkoxylated compounds into the process to prepare the detergents disclosed within each reference.